15 August 2002
Drydock Orientation Effect. In some cases, through necessity or choice,
a drydock may be oriented with the axis at an acute angle to the general shoreline.
Advantage. This orientation is advantageous where, similar to a river,
there is a current parallel to the shoreline, in which case the slanted position precludes
the necessity of having a ship abreast of the current flow when entering or leaving the
Modifications. Turning basin layouts are modified by such positioning,
but the guidance for clearance of structures flanking the entrance must be observed.
FITTING OUT/REPAIR PIERS. Fitting out or repair piers should be
provided adjacent to drydocks.
Existing Piers. In planning drydocks for existing shipyards, it may be that
existing piers can serve this purpose for ships to be built or overhauled in the dock. The
locations of such piers might influence positioning new drydocks reasonably near the
piers, but the importance of this is not great since it involves only a single transfer of the
ship after undocking.
New Piers. When fitting out/repair pier capacity does not exist, new piers
must be included in the project as essential support for drydocks. Refer to MIL-HDBK-
1025/1A, Piers and Wharves, for pier design.
SILTING AND SCOURING. Ascertain the stability of the access
waterway with regard to silting or scouring. A prospective site should be reconsidered if
the possibilities of silting or scouring indicate excessive future dredging maintenance.
Study historical characteristics of the waterway and possible effects on current flow due
to planned new work or anticipated future structures.
TOPOGRAPHY, HYDROLOGY, AND METEOROLOGY
Site Conditions. Prior to the design of a drydock, certain minimum
information is required about conditions at the proposed site. Drydock construction
methods used are usually closely related to site conditions and to the type and shape of
Yard Grades. The coping of a new drydock must be compatible with
general grades in a yard, or at least the grades in the vicinity of the drydock and
supporting facilities serviced by drydock cranes. Also, the elevation of the top of a
drydock must provide a certain minimum freeboard dependent on the highest
anticipated tides and waves.
Tide Range. Ascertain the tidal range. Use this information as a basis to
determine the final height of a drydock, and also the height and strength of cofferdams
or other temporary structures possibly involved in the drydock construction. For
predictions, which may be peculiar to the specific site, refer to records and predictions